The use of lymphocytes from axillary lymph nodes of mastectomy patients to generate human monoclonal antibodies

New heteromyeloma cell lines for the production of human monoclonal antibodies

The aim of this study was to establish hybridomas capable of long-term production of human monoclonal antibodies (mAbs). Heterohybridization was performed between the mouse myeloma cell line P3X63Ag8.653 and activated human peripheral blood lymphocytes (PBL). In order to achieve better retention of human chromosomes, as well as to improve the stability of the heterohybrids, one HAT-sensitive immunoglobulin (Ig)-non-secreting human x mouse (h x m) heteromyeloma was fused for a second time with activated human PBL. In this way, a panel of HAT-sensitive Ig-non-secreting h x h x m heteromyelomas was obtained and tested for its ability to generate stable human Ig-secreting heterohybrids with activated human PBL. Six lines were selected on the basis of their enhanced characteristics of fusion efficiency and genetic stability. When fused with in vitro immunized human PBL, they generated several h x h x h x m hybridomas stably secreting high yields (10-23 micrograms/ml/24 h) of human mAbs reactive with recombinant HBV core antigen (rHBcAg). Moreover, a continuous production of human Ig was observed when two h x h x m heteromyelomas, previously made ouabaine-resistant, were hybridized with EBV-transformed lymphoblastoid cell lines. These h x h x m heteromyelomas are ideal fusion partners for the production of human mAbs.

Monoclonal antibodies reactive with human breast or ovarian carcinoma: in vivo applications

Monoclonal antibodies (MoAbs) are unique and useful bioprobes that allow in vivo targeting of membrane-associated or circulating antigens. Most of the clinical trials to date have used low dosages of radiolabeled MoAb given in a single dose. Newer studies have included antibody fragments, repeated injections, intraperitoneal (IP) administration, and other labels such as 90Y. Clinical MoAb trials are often arduous, expensive, and time-consuming to perform. Before human use, animal studies and extensive MoAb characterization are required. The production of pharmaceutical grade, radiolabeled MoAb is technically difficult and costly. Clinical trials require administrative and patient consent as well as extensive written protocols. These studies necessitate interdepartmental and intradepartmental cooperation and coordination. Furthermore, the use of in vivo radiolabeled probes impacts many levels of health care providers from janitorial, nursing, and technical staff to laboratories and physicians. Simple blood tests or disposal of body excretions may concern nursing or technical staff with the possibility of radiation exposure. The responsibility for study design, personnel involvement, and prospective use in patients without a definitive cancer diagnosis ultimately rests with the physician. While many issues have been addressed, additional clinical trials, consideration of safety issues, and standardization between institutions will be necessary before the use of radiolabeled MoAb for diagnosis, management, or therapy of human tumors becomes routine. Continued cooperation and funding should ensure its achievement.

Human monoclonal antibodies directed against ovarian carcinoma

In order to obtain human monoclonal antibodies for immunodetection or treatment of ovarian carcinoma, we generated hybridomas by fusing peripheral blood lymphocytes of patients with ovarian carcinoma and the mouse myeloma cell line X63.Ag8.653. The patients were immunized prior to collection of peripheral blood lymphocytes with autologous tumor cells admixed with New Castle Disease Virus. Immunocytologic studies of hybridoma supernatant with tumor cells fixed with methanol and air-dried tumor cells indicated that all 14 antibodies reactive with tumor cells were directed against cytoplasmic or nuclear antigens. One hybridoma designated as 1B3 was very stable and secreted a specific IgM antibody. This cell line expanded in nude mice and the monoclonal antibody 1B3 was effectively purified from ascites or supernatant fluid. In experiments with tissue sections partly derived from the patient whose peripheral blood lymphocytes were used for fusion, biotinylated 1B3 recognized ovarian tumor cells. There was no significant cross-reaction against normal tissue from stomach, small intestine, colon, lung, kidney, endometrium, placenta, or lymph node. Mammary carcinoma preparations were also stained by 1B3 while normal breast tissue was negative.

The construction and use of a human-mouse myeloma analogue suitable for the routine production of hybridomas secreting human monoclonal antibodies

A human-mouse myeloma analogue termed HMMA2.11TG/O was constructed by fusion of the mouse myeloma cell line P3x63Ag8.653, a mutant derivative of MOPC21, with bone marrow mononuclear cells from a patients with IgA myeloma. The HMMA2.11TG/O cell line is resistant to 6-thioguanine and ouabain and sensitive to HAT. The cell line secretes no detectable immunoglobulin and has a hybrid karyotype and cell surface phenotype. An average fusion efficiency for growth of hybridomas of 1/17,000 fused cells was obtained in fusions with human peripheral blood mononuclear cells (PBM), Pokeweed Mitogen (PWM) stimulated PBM, and Epstein-Barr Virus (EBV) transformed polyclonal B cell lines. Over 75% of hybrids secrete detectable immunoglobulin and the cloning efficiency of the hybrids at 1 cell/well averages 25%. Antibody secreting cloned hybridoma cell lines were obtained by fusion directly with PBM from an immunized volunteer and by fusion with in vitro, secondarily immunized, EBV transformed polyclonal cell lines. Five hybridomas secreting human monoclonal IgM anti-tetanus antibodies and 2 secreting human monoclonal IgG anti-tetanus antibodies were selected and cloned from 6 fusions performed specifically for anti-tetanus antibody. Immunoglobulin and antibody secretion by cloned hybrids has been stable for 5-10 months at present. Immunoglobulin and antibody secretion in routine cultures passaged every 3-4 days has been 8-42 micrograms/ml. This human-mouse myeloma analogue should prove useful for the routine production of human monoclonal antibodies.

Generating human monoclonal antibodies

Present methods and systems for the generation of human monoclonal antibodies are briefly reviewed. The specificities of the available reagents are outlined. It would appear that the generation using hybridoma methods of human monoclonal antibodies to human tumor cell surface antigens is a rare event and that methods of in vitro immunostimulation may have to be used if such antibodies are to be reliably produced.

Monoclonal antibodies in clinical medicine--a review

Monoclonal antibodies are produced by the cell fusion method, whereby immune murine spleen cells are fused with a murine myeloma to produce large quantities of specific homogeneous antibodies. These have obvious advantages over conventional antisera particularly for in vitro diagnostic procedures. The use of monoclonal antibodies to human T cells, leukaemias and solid tumours are reviewed. In these areas, monoclonal antibodies are now being used for the diagnosis of disease activity, for the monitoring of graft rejection, and for the in vivo treatment of leukaemia and graft rejection in man. Murine monoclonal antibodies--examples of genetic engineering--represent a new and early phase of the use of molecular biological techniques for the production of reagents of use in clinical medicine.

Human hybridomas from patients with malignant disease

Lymphocytes from 180 patients with a variety of malignant diseases were collected and fused with a human myeloma-derived line, LON-LICR-HMy2/CAM1. A total of 162 hybridomas was obtained. Only B lymphocyte markers were found on the surface of the fusion products. Flow cytometric analysis revealed a stably increased DNA content in the hybridoma cells. Some hybridoma supernatants were found to contain new Ig chains. Anti-tumour binding activity was found in 12 supernatants.

A human-hybridoma system based on a fast-growing mutant of the ARH-77 plasma cell leukemia-derived line

A rapidly-growing, HAT-sensitive cell line LICR-LON-HMy2 has been derived from the ARH-77 human plasma cell leukemia-derived line. It lacks the enzyme hypoxanthine phosphoribosyltransferase (EC 2.4.2.8). Hybrids have been reproducibly made for more than a year and in independent laboratories with lymphocytes from tonsils, lymph nodes and peripheral blood and tonsil lymphocytes cultured with antigens. The parent line and hybrids are very robust in culture and double in 20-30 h. Hybrids clone easily and have stable karyotypes, most with modal numbers in the sixties. Stable Ig secretion patterns have been observed over 20-30 passages, and after cloning. It was estimated that about half the hybrids produce new immunoglobulin chains in addition to the parent cell line's IgG1 (kappa light chain). High, but not limiting, density hybridoma cultures (approximately 5 x 10(5) cells/ml) typically produce 0.25-2 micrograms/ml immunoglobulin per day, but some hybrids produce more. A high-secreting variant of LICR-LON-HMy2 has been derived. The LICR-LON-HMy2 line is human and is distinct from the HAT-sensitive human B cell-lines SKO-007 and GM 1500-6TG Al 2. It is available for distribution.

The immunohistochemical reactivity of a human monoclonal antibody with tissue sections of human mammary tumors

Human monoclonal antibodies have been generated following the fusion of human lymphocytes (obtained from axillary lymph nodes of mastectomy patients) with a murine nonimmunoglobulin secreting myeloma cell line. We report a detailed analysis of the reactivity of a human IgM monoclonal antibody secreted by one of these double cloned hybridoma cell lines. Tissue sections of both malignant and benign human mammary tumors, as well as apparently normal tissues, were tested using the immunoperoxidase technique and the human monoclonal antibody. Eighty-one per cent (54/67) of primary malignant mammary tumors, 100% (20/20) of metastatic breast lesions, and 14% (3/22) of benign breast lesions reacted positively with a moderate for strong intensity. The per cent of mammary carcinoma cells that stained and the pattern of staining varied among different tumor samples. While reactivity was observed with selected carcinomas of nonbreast origin, little or no reactivity was observed with apparently normal human tissues including normal mammary epithelium. The antibody reactivity observed was shown to be clearly distinct from those of both anti-T and anticarcinoembryonic antigen sera.